1. Field of the Invention
The present invention relates to a device for smoothing down a running material web.
2. Prior Art
A device for smoothing down a material web is known from German Patent DE 28 53 519 A1. The device has several threaded spindles which are rotated by a motor, so that their threads pull the material web toward the edges. To adapt the smoothing effect of the device to the material web, one roll is swivel-mounted, so that it is possible to adjust the looping angle of the material web around the threaded spindles.
A similar device is known from U.S. Pat. No. 2,639,483 which has three threaded spindles arranged one after the other, and a roller arranged upstream of the spindles. The material web is taken from the top of a stack and reversed on the roller. The material web is fed to the threaded spindles in a plane extending approximately through the spindles. This assures that the individual threaded spindles are looped by the material web in a defined way and, therefore, exert a constant smoothing effect on the material web.
Since the threaded spindles of the known devices only overlap the marginal edge of the material web and do not extend across the entire width of the material web, there is a risk that the material web will catch on the free ends of the threaded spindles. When samples are taken from the material web, or when two webs are sewn together, a hole in the material web can get caught on the tip of the threaded spindle. In this case, the material web tears, or the smoothing device is damaged, requiring the equipment to be shut down.